The invention is directed to gold alloy wires for jewelry, especially for jewelry chains which consists of a solder containing nucleus and a jacket of gold alloy.
So-called gold-solder nucleus wires are preferably used for the production of jewelry chains. These gold-solder nucleus wires consist of gold alloys of the desired fineness which contain a nucleus of a lower melting gold alloy. The gold fineness content of the wires for the most part is 8, 9, 14 or 18 carat in various gold colors (white gold, yellow gold, etc., according to the compounds of the alloy). Chains are prepared from these wires on special machines, which chains then are treated with flux materials and talcum powder. Subsequently they are heated in continuous heating oven whereby in the link, i.e., the contact place of two wire ends of each chain member a small amount of solder must be melted in order that there is formed a solder joint of sufficient strength inside each chain member.
In place of solder nucleus wires there are also employed solid wires of gold alloys, likewise in a fineness content of 8, 9, 14 or 18 carat. The working of these wires of jewelry chains is substantially more expensive since a powdery solder must be applied in the narrow links in order that there can be formed a solder joint of sufficient strength between the wire ends of each chain member. These powdery solders are mostly very low melting, non-noble metal containing gold alloys which shift the fineness content of the finished chain member toward lower values. Because of the strict chasing specification this reduction in the fineness content is a great disadvantage.
A greater portion of the jewelry chains are additionally shaped by rolls and are turningly worked with diamond tools (so-called diamonding). It is important thereby that the gold fineness content of the chain not be changed in these additional operations.
With the previously known gold alloy nucleus wires it is a matter of wires which consist of a jacket of a gold alloy which depends on the desired fineness and color and a nucleus of a lower melting gold alloy which serves as solder. The fineness content of this solder nucleus is usually the same as the outer jacket, in individual cases even lower. In order to guarantee a safe solder proportion, the liquidus and solidus temperatures of jacket and nucleus differ about 100.degree. C.
However, many gold alloys with non-noble metal insertions above all with decreasing carat number become increasingly hard and more difficult to shape. Above all from this there results in the previously known gold-solder nucleus wires increased difficulties in manufacture, especially through embrittlement and wire breaks. If gold-solder nucleus wires are manufactured with outer jacket and nucleus of the same carat number, with the provision that for the jacket and nucleus gold alloys are used of good ductility and sufficient difference in liquidus and solidus temperatures there cannot be chosen any colors desired for the gold alloys. Previously there were known only solder nucleus wires with 9 carats, which under these conditions could be produced with defensible operating expense.
Gold-solder nucleus wires are only diamondizable if the solder nucleus has the same fineness as the jacket. If solder nuclei are used of lower fineness then the fineness content of the diamondized jewelry chain is reduced considerably compared to the solder nucleus wire.
The for the most part hard gold solder nucleus wires which for the most part still contain brittle solder nuclei are only limitedly suited for the production of profile wires with for example, rectangular and semicircular cross section. Frequently in these profiles produced by rolling and drawings there are observed wire ruptures and breaks at the edges. Besides the solder nucleus is frequently crushed to irregular shapes.
A further disadvantage of the previously known gold solder nucleus wires is that because of the relatively large portion of solder, which is caused by the manufacturing process, the solder flux is very difficult to influence in the soldering of the chains. Too much solder occurs at the links of individual chain members so that the chain becomes unusable.
Therefore it was the problem of the present invention to create gold alloy wires for jewelry, especially for jewelry chains consisting of gold soler containing nucleus and a gold alloy jacket, which do not have the above described disadvantages, particularly permit any desired selection of fineness and gold color and also are capable of being chased in the diamondization. Besides they should be easily producible and processible.